Determinants for the Diet of Captive Agoutis (Dasyprocta spp.) a,b, Deborah A. McWilliams, MSc * KEYWORDS Dasyprocta Diet Rodentia Agouti Captive Nutrition Frugivore Omnivore Sparse attention in the literature has been given to the considerations for an appro- priate, practical diet for captive animals of the genus Dasyprocta (order Rodentia, family Dasyproctidae, common name agouti). Dasyprocta includes 11 extant species distributed throughout Central America, South America, and some associated islands (Coiba Island Panama, Roatan Island Honduras, and the Lesser Antilles). The species name, common name and average weights of the species in this genus are listed in Table 1.1,2 These species are terrestrial rodents that prefer neotropical savannas and evergreen forests.3,4 All species of Dasyprocta are diurnal5 and are classified as scatter-hoarding frugivores.6–9 Current species holdings in zoos that participate in the International Species Information System (ISIS) include Dasyprocta azarae, D cris- tata, D fuliginosa, D leporine (and subspecies), D mexicana, D prymnolopha, and D punctata (and subspecies).10 Species in the genus Dasyprocta resemble pacas but they are larger and more slender.11 Dasyprocta are not burrowers,8,11,12 although they use crevices or existing burrows for birthing and raising pups.11–13 DIET CLASSIFICATION There is much evidence supporting classification of Dasyprocta species as a frugi- vore.6–9 For example, D leporine is reported to have a wild diet that is 87% fruit, 6% animal matter, 4% fibrous foods, and 2% leaves.8,9 There is an equal—if not over- whelming—amount of evidence that species of Dasyprocta are omnivores, however. Dasyprocta, as members of the order Rodentia, have the generalist feeder, rodent dentition to support an omnivorous adaptation.14 Similar to most caviomorphs, the a American Association of Zoos and Aquariums Rodent, Insectivore and Lagomorph Taxon Advisory Group (AZA RIL-TAG), USA b Canadian Association of Zoos and Aquariums Nutrition Advisory Group (CAZA-NARG), 807-40 Vanier Drive, Guelph, ON, N1G 2X7 Canada * Canadian Association of Zoos and Aquariums Nutrition Advisory Group (CAZA-NARG), 807-40 Vanier Drive, Guelph, ON, N1G 2X7 Canada. E-mail address: [email protected] Vet Clin Exot Anim 12 (2009) 279–286 doi:10.1016/j.cvex.2009.01.001 vetexotic.theclinics.com 1094-9194/09/$ – see front matter ª 2009 Elsevier Inc. All rights reserved. 280 McWilliams Table 1 Species name, common name, and average weights of species in the genus Dasyprocta Species Common Name AverageWeight (kg) Dasyprocta azarae Azara’s agouti 2.711 2–41 3.82 Dasyprocta coibae Coiban agouti — Dasyprocta cristata Crested agouti — Dasyprocta fuliginosaa Black agouti 3.5–65 2.711 Dasyprocta guamara Orinoco agouti — Dasyprocta kalinowskii Kalinowski’s agouti — Dasyprocta leporinaa Brazilian agouti or 3.0–5.913 orange-rumped agouti 2.72,6,11 4.0–5.88 Dasyprocta mexicana Mexican agouti 2.0–4.05 Dasyprocta prymnolopha Black-rumped agouti 3.1–4 kg11 Dasyprocta punctataa Central-American agouti 3.0–5.25 3.1–411 2–41,27 Dasyprocta ruatanica Ruatan Island agouti — a There are subspecies. dental formula of Dasyprocta species is I 1/1, C 0/0, P 1/1, M 3/3.11 The incisors are continuously growing with restricted enamel on the anteroventral surface that is resis- tant to compressive strain and has a sharp edge for shaving and chiseling.14 The jaw can move forward and create two occlusions: the incisors occlude (for gnawing and chiseling) but the cheek teeth do not, or the cheek teeth occlude (for mastication) and the incisors do not. When the incisors are occluded and used for chiseling nonfood items, the skin of the upper lip can close off the mouth cavity to prevent entry of nonfood material. In general, the upper incisors can cut vegetation and pierce inver- tebrates or the flesh of vertebrates, and the lower incisors can cut and shear food, including flesh. The cheek teeth are used for grinding and chewing foods, including animal and plant foods. Further support for classification of Dasyprocta species as omnivores is the denti- tion wear patterns described in wild caviomorph rodents. In one study, a lack of distinctive wear patterns prevented diet specialization classification of wild Dasyprocta as a frugivore, folivore, hard-object specialist, browser, or grazer.15 The dental wear patterns, or lack of patterns, seem to support that these animals are not specialist feeders. Information provided by field studies also supports classification of Dasyprocta species as omnivores. For example, wild Dasyprocta eat: Fruit: citrus fruit and coconuts7,16; avocado, mango, pineapple, tomato, papaya, melon7; Syagrus romanzoffiana (Queen palm, Arecaceae).4 Plants: leaves,3,9 flowers,3,16 roots.3 Grains: corn, rice.16 Nuts and seeds: fruit seeds,3 almonds,3 Astrocaryum standleyanum (black palm) seeds,17 brazil nuts (Bertholletia excelsa),18 dry palm pyrenes (eg, Bactris Determinants for the Diet of Captive Agoutis 281 acanthocarpa, B excelsa, bactris palm),18,19 Hymenaea courbaril L (guapino, locust) seeds,20 Ormosia arborea (Legumindae) and Mimusop coriacea seeds,21 S romanzoffiana.4 Animal Matter: invertebrates.3,9,13,22 Various researchers also report omnivory in Dasyprocta. For example, during the fruit season, Dasyprocta ate a diet of 37% fruit pulp and 44% fruit seeds supple- mented with plant and animal matter. In the off-season, food caches (mostly seeds) and roots were eaten as well as plant and animal matter.3,9,13,17,22 With some variation due to climate and location, fruiting season is from March to June. In addition, there is little to no evidence of dietary specialization in either female or male Dasyprocta. The lack of dietary variation between the sexes in Dasyprocta can probably be attributed to the sharing of territories and common food sources for males and females.9,13,20,23 The evidence supporting omnivory in Dasyprocta species, in general, affects other determinants of dietary requirements in captives. GASTROINTESTINALTRACT There is a lack of detail describing the physiology of the gastrointestinal tract (GIT) of Dasyprocta species, which might be attributed to the assumption of frugivory and assumptions of homology with species that have been studied, such as the guinea pig (Cavia porcellus) and the paca (Agouti paca). These assumptions of frugivory and of homology with other species mean that there is a tendency for literature to rely on existing information for other species. At this time, there is also a lack of any evidence of cecotrophy. ENDOGENOUS ASCORBIC ACID There is some conflicting evidence for the physiologic ability of Dasyprocta species to endogenously synthesize ascorbic acid. In support of the need for a dietary source of ascorbic acid, the assumption of classification as a frugivore would indicate lack of an evolutionary ability to endogenously create ascorbic acid.7 Captive Dasyprocta seem to preferentially select foods high in ascorbic acid and this may indicate an inability to synthesize ascorbic acid.7 Such an apparent preference may only indicate a prefer- ence for the palatability of those foods higher in ascorbic acid, however (eg, mango, pineapple). Classification as an omnivore supports endogenous ascorbic acid synthesis in Dasyprocta. In addition, because fruits are only available for 4 to 5 months per year, it is questionable how Dasyprocta species obtain sufficient dietary sources of ascorbic acid during the off-season. A study on the biosynthesis of ascorbic acid in the acouchi and agouti further supports endogenous ascorbic acid synthesis in Dasyprocta. This study reports that both species have the ability to produce endogenous ascorbic acid.24 SCATTER-HOARDING BEHAVIOR Dasyprocta species are terrestrial scatter-hoarders and various studies report similar caching behavior.8,9,23,25 In general, seeds (and nuts) are cached one at a time after the pulp of a fruit is eaten or discarded8,20,23 and retrieved at some point after the fruit- ing season.9,23 Retrieval can be as long as 8 months after burial.23 Caches are covered with soil and usually a leaf or twig is placed on top after burial in a hole 2 to 8 cm deep.23 282 McWilliams METABOLIC RATE The metabolic rate of Dasyprocta species varies according to territorial conditions or the housing conditions of captives.16 For example, males bonded to a female are more active and have higher respiration rates and body temperatures (use more energy) than animals housed alone, male/male or all-male groups, or male and female non- bonded pairs. The activity of bonded males seems to be related to territoriality, and behaviors include digging, scrape-marking, and scenting.26 Adult males defend their territory against any male at any time but adult females only defend their territory when food is scarce.11 An equation for estimating basal metabolic rate for Dasyprocta species from 2.7 to 3.3 kg is 8.78 Â weight (kg).27 In general, females weigh more than males.9 APPARENT DIETARY REQUIREMENTS Studies on the captive diets of Dasyprocta are nonexistent. Captive Dasyprocta are reported to eat carrots, potatoes, cassava, and cooked ground beef.23 In general, they eat meat only if cooked but this does not mean they will not eat uncooked flesh. For example, a group of captive Dasyprocta killed and ate an adult male Liomys pictus (painted spiny pocket mouse).23 The high proportion of seeds and nuts in the diets of wild Dasyprocta along with the selection of foods higher in energy and lower in water content in captive animals7